Questions

No. The sheets tell you which square gets which color and how tall to stack it. You will pick up the rest as you go along.

Honestly, we do not know. We are aiming to finish inside one semester, but a lot depends on how many people turn up.

The 18 baseplates do not all come out at once. We put out a few at a time, with the sheets that go with them, which keeps the table manageable.

Expect a new batch about once a week. If the building goes quickly we will put more out and if it goes slowly we will wait.

The board is built in two passes. In Phase 1 we build the terrain in grays and in Phase 2 we add the geology colors on top afterwards. You can join in at either one without having done Phase 1 first.

Come whenever suits you. There is no session you need to be at and nothing to sign up for. Drop in for 5 minutes or stay the afternoon!

Yes of course! It's just LEGO after all. Pull it off and put the right one on.

The same goes if you spot something wrong that somebody else built. If it looks easy to fix, please go ahead and if it does not, come and let us know.

It goes on display. Since the 18 baseplates do not clip to one another, the finished map will need a rigid board behind it to hold everything square.

Please do, we would love that. The colors and the plate counts are listed on the Materials page and the code that generated them is open too.

The plate counts and the code →

18 baseplates was a good number to fit on a table and to fit within our budget. Each one is 32 x 32 studs, or 16 x 16 of our 2x2 squares. A grid 6 across and 3 down gives us 96 x 48 squares, or 1.54 x 0.77 m of Mars.

A bigger board would give us a sharper map, but the cost climbs very quickly. Doubling the detail in both directions would need 4 times the bricks, 4 times the money, and 4 times the table.

Real Mars runs from about −7.2 km at the bottom of Hellas up to nearly +20 km on top of Olympus Mons, which is a range of roughly 27 km. If you chop that into 2 km steps, the tallest stack comes out at 14 plates, or about 45 mm.

The project has cost about $1,225 so far.

The 12,000 gray and white plates came from BrickLink for around $690 and the colored ones came from LEGO Pick a Brick.

The finished model will weigh somewhere around 15 kg.

Mostly by what LEGO actually makes. If there is no 2x2 plate in a color then we cannot use it. LEGO makes them in a limited range of colors.

For Phase 1 the 3 elevation bands are Dark Bluish Gray, Light Bluish Gray, and White. They are cheap in bulk, they are easy to tell apart even under bad lighting, and they cycle cleanly as the stacks climb.

For Phase 2 we should warn you that the colors look nothing like the real units. Mars is visually quite limited, mostly shades of rust and dust. A true color map of it would be unreadable.

Instead we picked colors that are only reminiscent of what each unit is, chosen so they can be told apart across a table.

We used the Hammer projection, sometimes called Hammer-Aitoff, which squeezes the whole globe into an ellipse.

We picked it because it is equal-area. Each 2x2 plate stands for the same amount of ground and the brick counts can then be read as areas.

The ellipse is also why the board has bare corners, 980 of them.

More on flattening a sphere →

We used two published datasets, both free to download.

The heights come from MOLA, the Mars Orbiter Laser Altimeter. It flew on Mars Global Surveyor and bounced a laser off the planet through the late 1990s to measure its shape.

Smith, D. E. et al. (2001) Mars Orbiter Laser Altimeter: experiment summary after the first year of global mapping of Mars. Journal of Geophysical Research 106(E10), 23689–23722.

The colors come from the United States Geological Survey's geologic map of Mars, published in 2014.

Tanaka, K. L. et al. (2014) Geologic map of Mars. U.S. Geological Survey Scientific Investigations Map 3292.

The topography, in full →

The geology, in full →

We used GMT, the Generic Mapping Tools, to reproject the global grids and bin them down to 96 x 48 squares.

We used Python for the rest of the analysis. It calculates the stack height and unit of each square, counts the bricks needed in each color, and produces the printed sheets, using numpy and rasterio.

We used Three.js to draw the 3D model on this site.

We bought the bricks from LEGO Pick a Brick and BrickLink.

Earth's diameter is 12,742 km against Mars at 6,779 km, which at the scale of this board gives

An Earth would fit next to our Mars on the same table, since the board is 1.54 m wide.

The comparison by area is closer. The whole surface of Mars comes to about 144 million km² and all the dry land on Earth to about 149 million km². Every desert, forest, mountain range, and city on Earth would tile onto the board.

Everest is 8.85 km above sea level. Our plates are 2 km each.

The biggest mountain on Earth would come up to about the knee of the biggest one on Mars. On a board scaled honestly in both directions, Everest would stand 0.64 mm tall and you would need a magnifying glass to find it.

Olympus Mons is 22 km tall but roughly 600 km wide, so its flanks slope at about 5 degrees, which is gentler than a lot of roads. You could walk up it for days without ever feeling like you were climbing a mountain, and the summit would stay below the horizon the whole way. So no, you would not know!

The same holds for any tall stack on this table, which looks dramatic only because we stretched the model 22 times. Anyone standing on the real surface would find a gently sloping desert.

Earth has three processes that flatten its surface. On Mars each one is absent or much weaker.

No plate tectonics. On Earth the crust slides around. A volcano drifts off its hot spot and dies young, which is why Hawaii is a chain of them. On Mars the crust stays put, letting a single volcano remain over the same plume for billions of years and keep growing.

Weaker gravity. Mars pulls at about 38 percent of Earth's and a mountain can pile much higher before its own weight makes it slump.

Almost no erosion. Mars today has neither rainfall nor running water nor an ocean to erode its coasts. Craters formed nearly 4 billion years ago are still visible. On Earth the same craters would have been eroded, buried, or destroyed at a subduction zone.

The slider sets a sea level and any square lower than it goes under. It starts at −2 km, which is roughly the Arabia shoreline.

The water pools in the north, in one connected sheet, because the northern third of Mars lies kilometers lower than the south. That step in elevation is the crustal dichotomy, reproduced on the board from the heights alone.

Did it actually happen? That is still debated. People have traced possible old shorelines around the northern plains for decades. The higher, older one is called Arabia while the lower, younger one is called Deuteronilus. Arabia runs at roughly −2 km and Deuteronilus at roughly −4 km, which on this board are the tops of the 4th and 3rd plates.

The trouble is that an ocean surface has to be level and those traced shorelines are not. They wander up and down by kilometers, for a long time the strongest argument that they were never coastlines.

Two explanations have been put forward. Both hold that the shorelines were level when they formed and were bent afterwards.

Our own Prof. Taylor Perron showed in 2007 that true polar wander, a reorientation of the whole planet relative to its spin axis, would leave an old shoreline deformed in the pattern these show.

Others argued in 2018 that Tharsis was still growing while the shorelines formed, with the weight of the volcanic pile deforming the surface as it accumulated.

Where would you put the shoreline? A single plate is 2 km of height and 222 km of ground, which puts a real shoreline far below what the board can resolve.